US20190145571A1 - Insulating material and device using insulating material - Google Patents

Insulating material and device using insulating material Download PDF

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Publication number
US20190145571A1
US20190145571A1 US16/228,742 US201816228742A US2019145571A1 US 20190145571 A1 US20190145571 A1 US 20190145571A1 US 201816228742 A US201816228742 A US 201816228742A US 2019145571 A1 US2019145571 A1 US 2019145571A1
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Prior art keywords
insulating material
nonwoven fabric
fiber
silica xerogel
fabric fiber
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US16/228,742
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English (en)
Inventor
Kazuma Oikawa
Kei Toyota
Shinji Okada
Shigeaki Sakatani
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD. reassignment PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: OIKAWA, KAZUMA, OKADA, SHINJI, SAKATANI, SHIGEAKI, TOYOTA, KEI
Abandoned legal-status Critical Current

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    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
    • F16L59/028—Compositions for or methods of fixing a thermally insulating material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
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    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/245—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it being a foam layer
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    • C04B38/0045—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by a process involving the formation of a sol or a gel, e.g. sol-gel or precipitation processes
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/413—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties containing granules other than absorbent substances
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/04—Arrangements using dry fillers, e.g. using slag wool
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D23/00—General constructional features
    • F25D23/06—Walls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
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    • B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/02—Composition of the impregnated, bonded or embedded layer
    • B32B2260/021—Fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
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    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/04—Impregnation, embedding, or binder material
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    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
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    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/304—Insulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
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    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/306—Resistant to heat
    • B32B2307/3065—Flame resistant or retardant, fire resistant or retardant
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • C—CHEMISTRY; METALLURGY
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
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    • C04B2111/00612—Uses not provided for elsewhere in C04B2111/00 as one or more layers of a layered structure
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
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    • C04B2111/20—Resistance against chemical, physical or biological attack
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Definitions

  • the technical field relates to an insulating material, and to a device using the insulating material. Particularly, the technical field relates to a flame-retardant insulating material, and to a device using such an insulating material.
  • Silica aerogel is a known insulating material.
  • Silica aerogel is produced by sol-gel reaction of raw material water glass (a sodium silicate aqueous solution) and alkoxysilane (e.g., tetramethoxysilane (TEOS)).
  • TEOS tetramethoxysilane
  • a composite material of silica aerogel and fiber is known that is produced by spraying a granular silica aerogel produced from alkoxysilane and having a thermal conductivity of 23 mW/m ⁇ K onto a two-component fiber material of a low-melting-point fiber and a high-melting-point fiber, and thermally compressing the composite of these materials under high temperature.
  • Japanese Patent No. 4237253 Japanese Patent No. 4237253
  • the low-melting-point fiber is thermally compressed at a temperature equal to or greater than the melting point of the fiber to bind the fiber to the silica aerogel, and the technique successfully reduces detachment of aerogel more effectively than conventionally achieved.
  • an insulating coating material containing a low-density powder material and a water-soluble polymer solution the low-density powder material being a powder material containing a porous powder such as silica aerogel.
  • a thin insulating material produced by applying the insulating coating material to a base material is also reported.
  • a low-density powder (silica aerogel) is mixed with a several ten weight % PVA aqueous solution to prepare an insulating coating material.
  • the coating material is then applied to copy paper to form a 10 ⁇ m-thick coating material layer, and another sheet of copy paper is laid over the coating material layer. These are then bonded and dried to obtain the insulating material (JP-A-2013-100406).
  • the present disclosure is intended to provide an insulating material that has high insulation capable of effectively blocking a heat flow even in narrow small spaces while providing flame retardancy with which spreading of fire can be prevented.
  • the present disclosure is also intended to provide a device using such an insulating material.
  • an insulating material that contains a silica xerogel, and a nonwoven fabric fiber capable of generating carbon dioxide by reacting with atmospheric oxygen at a temperature of 300° C. or more.
  • a device is used that uses the insulating material installed as a part of a heat insulating or a cold insulating structure, or installed between a heat-generating part and a casing.
  • the insulating material of the aspect of the disclosure has a lower thermal conductivity than traditional insulating materials, and can exhibit a sufficient insulating effect in narrow spaces of electronic devices, in-car devices, and industrial devices, and can effectively reduce transfer of heat from a heat-generating part to a casing.
  • the insulating material of the aspect of the disclosure is flame retardant, and, in addition to the insulating effect, has the effect to prevent spreading of fire in case of thermal runaway or a fire.
  • FIG. 1A is a cross sectional view of an insulating material of First Embodiment.
  • FIG. 1B is a cross sectional view of an insulating material of First Embodiment.
  • FIG. 2 is a perspective view of a silica xerogel of the embodiment.
  • FIG. 3A is a diagram showing the chemical formula of a flame-retardant nonwoven fabric material of the embodiment.
  • FIG. 3B a diagram showing the chemical formula of a flame-retardant nonwoven fabric material of the embodiment.
  • FIG. 4 is a diagram showing a chemical structure of a surface of a fiber of the embodiment.
  • FIG. 5A is a diagram showing a physical structure of a fiber of the embodiment.
  • FIG. 5B is a diagram showing a physical structure of a fiber of the embodiment.
  • FIG. 6 is a diagram representing a method for producing the flame-retardant insulating material of the embodiment.
  • FIG. 7 is a diagram showing how flame is brought into contact with the insulating material produced in Example 1.
  • FIG. 8 is a diagram showing how flame is brought into contact with the insulating material produced in Comparative Example 1.
  • FIG. 9 shows SEM images of cross sections of the insulating materials produced in Example 1 and Comparative Example 2.
  • FIG. 10 is a diagram representing the relationship between the filling rate of the silica xerogel of the embodiment, and thermal conductivity.
  • FIG. 11 is a diagram representing the relationship between fiber diameter and thermal conductivity in the embodiment.
  • FIG. 12A is a cross sectional view of a flame-retardant insulating material of an embodiment.
  • FIG. 12B is a diagram representing a method for producing the flame-retardant insulating material of the embodiment.
  • the cross sectional view in FIG. 1A shows an insulating material 103 a of an embodiment.
  • the insulating material 103 a is a single layer of nonwoven fabric fiber 119 and silica xerogel 104 .
  • the cross sectional view in FIG. 1B shows an insulating material 103 b of the embodiment.
  • the insulating material 103 b has a three-layer structure configured from a composite layer 102 of nonwoven fabric fiber 119 and silica xerogel 104 , and upper and lower silica xerogel layers 101 that contain the silica xerogel 104 but do not contain the nonwoven fabric fiber.
  • the insulating material 103 a and the insulating material 103 b use the same silica xerogel 104 and the same nonwoven fabric fiber 119 .
  • the insulating material 103 a is essentially the same as the composite layer 102 .
  • insulation can be provided by increasing the filling rate of the silica xerogel 104 in the composite layer 102 .
  • one of the upper and the lower silica xerogel layer 101 , or both of these layers on the composite layer 102 may be absent, provided that the thermal conductivity falls in the desired range below.
  • the nonwoven fabric fiber 119 has a thermal conductivity of 0.030 to 0.060 W/m ⁇ K.
  • the silica xerogel 104 has a thermal conductivity of 0.010 to 0.015 W/m ⁇ K.
  • the insulating materials 103 b and 103 a have a thermal conductivity of 0.014 to 0.024 W/m ⁇ K.
  • FIG. 2 shows a microstructure 111 of the silica xerogel 104 of the embodiment.
  • the silica xerogel 104 has a porous structure of interconnected point-contact silica secondary particles 109 as an aggregate of silica primary particles 108 , and the porous structure has pores 110 of several tens of nanometers.
  • the microstructure 111 of the silica xerogel 104 is present in the composite layer 102 , or in the upper and lower silica xerogel layers 101 , or an inorganic binder layer 105 .
  • the insulating materials 103 a and 103 b have a thickness of 0.03 mm to 3.0 mm, preferably 0.05 mm to 1.0 mm.
  • the insulating effect in a thickness direction of the insulating material 103 b becomes weak.
  • the insulating material 103 b can maintain the insulating effect in thickness direction when it has a thickness of 0.05 mm or more.
  • the insulating materials 103 a and 103 b cannot be easily incorporated in today's thinner and smaller devices.
  • the optimum range of the weight fraction of the silica xerogel 104 in the total weight of the insulating materials 103 a and 103 b varies with the basis weight, the bulk density, and the thickness of the nonwoven fabric fiber 119 , and there is no fixed value.
  • the weight fraction of the silica xerogel 104 is typically at least weight %. It becomes difficult to achieve a low thermal conductivity when the weight fraction of the silica xerogel 104 is less than 30 weight %. In the embodiment, the weight fraction of the silica xerogel 104 is 70 weight % or less.
  • the insulating material 103 b can still have a reduced thermal conductivity when the weight fraction of the silica xerogel 104 is higher than 70 weight %. However, in this case, the insulating material 103 b lacks sufficient flexibility and strength, and the silica xerogel 104 may detach itself from the insulating material 103 b after repeated use of the insulating material 103 b.
  • the nonwoven fabric fiber 119 is a fiber having a basis weight of 5 g/m 2 to 350 g/m 2 .
  • basis weight is the weight per unit area.
  • the nonwoven fabric fiber 119 have a bulk density of 100 kg/m 3 to 500 kg/m 3 .
  • the bulk density of the nonwoven fabric needs to be at least 100 kg/m 3 .
  • the spatial volume of the nonwoven fabric becomes smaller, and the amount of the silica xerogel 104 that can be filled becomes relatively smaller, with the result that the thermal conductivity increases.
  • the nonwoven fabric fiber 119 is preferably a carbon-containing nonwoven fabric fiber 119 capable of generating carbon dioxide by reacting with the atmospheric oxygen at a high temperature of 300° C. or more. Chemical fibers are not desirable as they melt at temperatures below 300° C., and form a dark clump.
  • the nonwoven fabric fiber 119 is described below using the structural formulae of FIG. 3A and FIG. 3B .
  • the nonwoven fabric fiber 119 is preferably an oxidized acrylic 113 with a partly remaining nitrile group, or a completely cyclized oxidized acrylic 114 .
  • the oxidized acrylic can be obtained by heating polyacrylonitrile (PAN) 112 in the atmosphere at 200 to 300° C.
  • PAN polyacrylonitrile
  • PAN 112 is not preferred for use in the fiber of the present embodiment because this compound burns itself when heated at higher temperatures.
  • More preferred for efficient generation of carbon dioxide are the carbon fiber 115 and the graphite fiber 116 shown in FIG. 3B .
  • nonwoven fabric fibers may be contained; however, the nonwoven fabric fiber 119 needs to be a main component of different nonwoven fabric fibers. Preferably, the nonwoven fabric fiber 119 is at least 50 volume % of all nonwoven fabric fibers. The nonwoven fabric fibers may be different nonwoven fabric fibers.
  • the nonwoven fabric fiber 119 used in the embodiment have a fiber diameter of 1 to 30 ⁇ m.
  • the insulating materials 103 a and 103 b have a large specific surface area, and can generate more carbon dioxide.
  • the insulating materials 103 a and 103 b also can achieve low thermal conductivity with such fibers because the solid component that transfers heat decreases.
  • the insulating material With a fiber diameter of larger than 30 ⁇ m, the insulating material has a reduced specific surface area, and generates less carbon dioxide. In this case, an effective flame-retardancy effect cannot be obtained, and the solid component that transfers heat increases. This results in increased thermal conductivity in the insulating materials 103 a and 103 b . From the standpoint of the thermal conductivity, flame retardancy, and productivity of the insulating materials 103 a and 103 b , it is therefore preferable that the fiber diameter of the nonwoven fabric fiber 119 be 1 to 30 ⁇ m.
  • the nonwoven fabric fiber 119 uses, for example, the oxidized acrylic 113 with a partly remaining nitrile group, the completely cyclized oxidized acrylic 114 , or the carbon fiber 115 or graphite fiber 116 , as mentioned above.
  • An acid is used in the process of mixing the nonwoven fabric fiber 119 and the silica xerogel 104 (as will be described below in (7) Hydrophobization 1 (dipping in hydrochloric acid)).
  • the acid modifies the surface of the nonwoven fabric fiber 119 with carboxyl (—COOH) 117 , as shown in the structure diagram of the nonwoven fabric fiber 119 in FIG. 4 .
  • the density of the carboxyl group 117 varies with the conditions of when the nonwoven fabric fiber 119 is dipped in a strong acid (acid concentration, time, and temperature).
  • the density of the functional group tends to increase as the concentration, time, and temperature increase.
  • the carboxyl group formed on the surface of the nonwoven fabric fiber 119 undergoes dehydrocondensation reaction in the process of forming the silica xerogel 104 (hydrophobization and drying).
  • a high density of carboxyl group 117 facilitates both an inter-fiber and an intra-fiber reaction in the nonwoven fabric fiber 119 , causing the nonwoven fabric fiber 119 to fuse, and form a double strand (where the fibers cross).
  • Such a thick double strand formed by the nonwoven fabric fiber 119 becomes a heat conduction pathway, and is not desirable in terms of an insulating material design.
  • the nonwoven fabric fiber 119 In order to reduce the dehydrocondensation reaction between the adjacent carboxyl groups on the surface of the same nonwoven fabric fiber 119 , it is preferable that the nonwoven fabric fiber 119 have a gently curved hairpin loop structure 120 formed in parts of the fiber.
  • FIG. 5A shows a fiber with such a hairpin loop structure 120 . Because the nonwoven fabric fiber 119 does not contact other nonwoven fabric fibers 119 , binding of nonwoven fabric fibers 119 can be reduced. It is also preferable that the nonwoven fabric fiber 119 have a pseudoknot structure 121 , which is a continuous structure of hairpin loop structures 120 joined together.
  • FIG. 5B shows a fiber having such a pseudoknot structure 121 .
  • the hairpin loop structure 120 and the pseudoknot structure 121 despite the diameter that does not differ from the diameter of the nonwoven fabric fiber 119 , effectively add strength to the weak structure of the silica xerogel 104 , which is light and has low elastic modulus, and is not suited as a structural material.
  • the hairpin loop structure 120 refers to a structure of a single fiber that is symmetric about a point on the fiber, and has a single bent portion (line symmetry).
  • the pseudoknot structure 121 refers to a structure of a single fiber that is bent side-by-side at two points on the fiber, and has two bent portions (rotational symmetry).
  • the nonwoven fabric fiber 119 should have low bulk density and low basis weight, for the same reasons described above.
  • the loop structure is not limited to the hairpin loop structure, and may be an internal loop, a bulged loop, or a branched loop. That is, the loop may be any loop, provided that the fiber has a loop structure (a ring or a ring-like structure), or a curved portion, in at least a part of the fiber.
  • the organic material In a resin-base foam insulation material, the organic material typically decomposes under heat when brought close to flame. The burning organic material generates a large quantity of flammable gas, and the insulating material violently burns when the flammable gas ignites.
  • the insulating materials 103 a and 103 b contain the silica xerogel 104 and the nonwoven fabric fiber 119 .
  • the surface of silica particles constituting the silica xerogel 104 is organically modified, and is hydrophobic. When the surface is heated to a high temperature of 300° C. or more for extended time periods, the organic modifying group undergoes heat decomposition, and releases a large quantity of a flammable gas, for example, such as trimethylsilanol.
  • the flammable gas may act as a combustion improver.
  • the base material itself is not combustible.
  • the glass paper of C glass may burn as a result of ignition of the flammable gas generated in large quantity from the silica xerogel 104 .
  • C glass has a lower heat resistance than E glass, and, depending on the basis weight, contracts and deforms when heated to 750° C. or more.
  • the carbon in the nonwoven fabric fiber 119 reacts with the atmospheric oxygen in a high-temperature atmosphere of 300° C. or more, and generates and releases a large quantity of carbon dioxide so that the flammable gas released from the silica xerogel 104 does not burn itself.
  • a method for producing the insulating material 103 b is schematically represented in FIG. 6 .
  • the following describes exemplary production of the insulating material 103 b , with reference to FIG. 6 .
  • the raw material silica is not limited to high molar sodium silicate, and may be alkoxysilane or water glass (low molar ratio).
  • the acid examples include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, chloric acid, chlorous acid, and hypochlorous acid; acidic phosphates such as acidic aluminum phosphate, acidic magnesium phosphate, and acidic zinc phosphate; and organic acids such as acetic acid, propionic acid, oxalic acid, succinic acid, citric acid, malic acid, adipic acid, and azelaic acid.
  • the acid catalyst used is not particularly limited. However, preferred is hydrochloric acid from the standpoint of the strength of the gel skeleton, and the hydrophobicity of the silica xerogel 104 .
  • the sol solution prepared by adding the acid catalyst to the high molar silicate aqueous solution is gelled.
  • the sol is turned into a gel in a sealed container so that the liquid solvent does not evaporate.
  • the pH is preferably 4.0 to 8.0.
  • the high molar silicate aqueous solution may fail to gel when the pH is less than 4.0, or more than 8.0, though it depends on the temperature.
  • the sol solution is used in an amount in excess of the theoretical spatial volume of the nonwoven fabric fiber 119 (>100%).
  • the theoretical spatial volume of the nonwoven fabric is calculated from the bulk density of the nonwoven fabric fiber 119 .
  • the material, the thickness, and the bulk density of the nonwoven fabric are not limited, as mentioned above.
  • Impregnation of the nonwoven fabric may be accomplished by dipping a roll of the nonwoven fabric in the sol solution one after another, or by applying the sol solution to the nonwoven fabric, roll-to-roll, through a dispenser or a spray nozzle while feeding the nonwoven fabric at a constant speed.
  • Preferred for productivity is the roll-to-roll method.
  • the material and thickness of the films attached to the impregnated nonwoven fabric subjected to gelation, thickness control, and curing are not limited to those exemplified above. However, because the curing requires heat, the films are preferably made of a resin material having a maximum tolerable temperature of 100° C. or more, and a coefficient of linear thermal expansion of 100 ( ⁇ 10 ⁇ 6 /° C.) or less, for example, such as polypropylene (PP), and polyethylene terephthalate (PET).
  • PP polypropylene
  • PET polyethylene terephthalate
  • the impregnated nonwoven fabric with the films is passed through a preset gap of 190 ⁇ m (including the film thickness) between two-axis rollers to squeeze out the excessive gel from the nonwoven fabric, and achieve a target thickness of 100 ⁇ m.
  • the method used to control the thickness is not limited to this, and the thickness may be controlled by using a squeegee or a press.
  • the gel sheet with the films is put in a container, and kept in a 85° C./85% constant-temperature and constant-humidity vessel for 3 hours to allow silica particles to grow (through dehydrocondensation reaction of silanol) and form a porous structure.
  • the curing temperature is preferably 50 to 100° C., more preferably 60 to 90° C.
  • the water in the container may evaporate, and separate from the gel, even when the container is sealed. This reduces the volume of the resulting wet gel, and the desired silica xerogel 104 may not be obtained.
  • the reaction can promote moderate growth of silica particles without decreasing productivity, and the point-contact neck portions of the adjoining silica particles can have increased strength. With this temperature range, curing also can proceed without evaporation of moisture from the wet gel.
  • the curing time is preferably 0.5 to 6 hours, more preferably 1 to 3 hours, though it depends on the curing temperature.
  • the curing time is less than 0.5 hours, the gel wall may fail to develop sufficient strength.
  • the gel wall strength improving effect of curing becomes weak, and productivity may decrease, instead of increasing.
  • the gel wall strength can sufficiently improve without decreasing productivity.
  • the temperature and humidity are inseparable from time. Considering the balance between improvement of gel skeleton and productivity, it is preferable that curing be performed for 1 to 3 hours under 85° C. and 85% conditions.
  • the gelation temperature and the curing temperature in the foregoing ranges, and to decrease the total time of gelation and curing within the foregoing ranges.
  • the curing container is taken out of the thermostat bath, and allowed to cool to room temperature.
  • the cured sample is then taken out of the container, and the films are removed.
  • the gel sheet is dipped in hydrochloric acid (4 to 12 N), and allowed to stand at ordinary temperature (23° C.) for at least 15 minutes to incorporate hydrochloric acid in the gel sheet.
  • the gel sheet is dipped in, for example, a mixture of octamethyltrisiloxane (silylation agent) and 2-propanol (IPA), and placed in a 55° C. thermostat bath to allow reaction for 2 hours. As soon as the trimethylsiloxane bond starts to form, the gel sheet releases hydrochloric acid water, and the solution separates into two layers (the siloxane is on the top, and the hydrochloric acid water and 2-propanol are at the bottom).
  • silation agent silation agent
  • IPA 2-propanol
  • the gel sheet is transferred to a 150° C. thermostat bath, and dried for 2 hours.
  • the method for producing the insulating material 103 b described above with reference to FIG. 6 is merely an example, and the method of production of the insulating material 103 b is not limited to this.
  • the insulating material 103 b was produced from nonwoven fabric fibers 119 of various basis weights (the weight of nonwoven fabric fiber 119 per unit area [g/m 2 ]) or various thicknesses, and was measured for thermal conductivity and thickness.
  • the thermal conductivity of the insulating material 103 b was measured with a heat flow meter HFM 436 Lamda (manufactured by NETZCH) and a TIM tester (manufactured by Analysis Tech).
  • the thickness was measured using a digimatic indicator H0530 (manufactured by Mitsutoyo Corporation), under a pressure of 7.4 kPa. Measurements were made at 15 points within a plane of ten sheets of insulating material 103 b (a total of 150 measurement points).
  • the insulating material was brought into direct contact with a flame, and evaluated for flammability.
  • the insulating material was determined as being acceptable when it had a thermal conductivity of 0.024 W/m ⁇ K or less, and not flammable even when brought into contact with flame. The overall evaluation result is acceptable with both of these conditions satisfied.
  • the thermal conductivity of still air at ordinary temperature is said to be typically about 0.026 W/m ⁇ K. Accordingly, the insulating material 103 b needs to have a smaller thermal conductivity than still air to effectively block a flow of heat.
  • the insulating material 103 b was determined as being acceptable when it had a thermal conductivity of 0.024 W/m ⁇ K or less, a value about 10% smaller than the thermal conductivity of still air.
  • the advantage against air insulation will be lost when the thermal conductivity is larger than 0.024 W/m ⁇ K, a value that does not greatly differ from the thermal conductivity of still air.
  • the insulating material was determined as being poor when it burned after several seconds under the flame, and acceptable when it did not burn under the same conditions.
  • Examples 1 to 4 and Comparative Examples 1 to 4 are configured from the insulating material 103 b (the composite layer 102 and the silica xerogel layer 101 ) shown in FIGS. 1A and 1B .
  • Comparative Examples 5 and 6 solely use the nonwoven fabric fiber 119 .
  • Comparative Example 1 represents an insulating material in which the nonwoven fabric fiber 119 is configured from polyester.
  • Comparative Examples 2 to 4 a flame-retardant oxidized acrylic was used as the nonwoven fabric fiber 119 , and samples with a fiber diameter of more than 30 ⁇ m were evaluated.
  • the evaluation results for Comparative Examples 5 and 6 are the results for flame-retardant nonwoven fabrics that did not contain the silica xerogel 104 . In the following, the concentrations are in weight %.
  • the impregnated nonwoven fabric with the films was passed through a preset gap of 0.3 mm (including the film thickness) between two-axis rollers to squeeze out the excessive gel from the nonwoven fabric, and achieve a target thickness of 0.30 mm.
  • the gel sheet with the films was put in a container, and kept in a 85° C./85% constant-temperature and constant-humidity vessel for 3 hours to allow silica particles to grow (through dehydrocondensation reaction of silanol) and form a porous structure.
  • the curing container was taken out of the thermostat bath, and allowed to cool to room temperature. The cured sample was then taken out of the container, and the films were removed.
  • the gel sheet was dipped in hydrochloric acid (6N), and allowed to stand at ordinary temperature (23° C.) for 60 minutes to incorporate hydrochloric acid in the gel sheet.
  • the gel sheet was dipped in a mixture of octamethyltrisiloxane (silylation agent) and 2-propanol (IPA), and placed in a 55° C. thermostat bath to allow reaction for 2 hours.
  • IPA 2-propanol
  • the gel sheet released hydrochloric acid water, and the solution separated into two layers (the siloxane is on the top, and the hydrochloric acid water and 2-propanol are at the bottom).
  • the gel sheet was transferred to a 150° C. thermostat bath, and dried for 2 hours in the atmosphere.
  • the resulting insulating material 103 b had an average thickness of 0.305 mm, and a thermal conductivity of 0.022 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 42.2 wt %.
  • FIG. 7 shows how flame was brought into contact with the insulating material produced in Example 1. As can be seen, the insulating material did not burn at all.
  • FIG. 9 shows scanning electron micrographs of the flame-retardant insulating materials (a composite of the nonwoven fabric fiber 119 of oxidized acrylic, and the silica xerogel 104 ) produced in Example 1 and Comparative Example 2.
  • the fiber of Example 1 is a fiber treated with 6 N hydrochloric acid.
  • the fiber of Comparative Example 2 is a fiber treated with 12 N hydrochloric acid.
  • the insulating material produced in Example 1 had a cross sectional structure (150 times) with a hairpin loop structure. The individual fibers were independent, and the fiber diameter was 15 ⁇ m.
  • a sheet was produced under the same conditions used in Example 1, except that the nonwoven fabric fiber 119 had an average thickness of 0.108 mm and a basis weight of 20 g/m 2 , and that the raw material was used in half the amount accordingly.
  • the resulting insulating material 103 b had an average thickness of 0.246 mm, and a thermal conductivity of 0.0180 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 66.9 wt %. The insulating material did not burn at all even when brought into contact with flame, as in Example 1.
  • Example 3 A sheet was produced under the same conditions used in Example 1, except that the nonwoven fabric fiber 119 contained 20% PET and 80% carbon fiber, and had an average thickness of 0.450 mm and a basis weight of 30 g/m 2 , and that the raw material was used twice the amount accordingly. Because carbon fibers do not occur as tangled fibers, and easily become loose, Example 3 used a carbon fiber base material that contained 20% PET as a binder so that a self-standing nonwoven fabric base material was obtained.
  • the resulting insulating material 103 b had an average thickness of 0.503 mm, and a thermal conductivity of 0.019 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 67.1 wt %. The insulating material did not burn at all even when brought into contact with flame, as in Example 1.
  • Example 4 A sheet was produced under the same conditions used in Example 1, except that the nonwoven fabric fiber 119 contained 20% PVA and 80% carbon fiber, and had an average thickness of 0.130 mm and a basis weight of 10 g/m 2 , and that the raw material was used in half the amount accordingly. Because carbon fibers do not occur as tangled fibers, and easily become loose, Example 4 used a carbon fiber base material that contained 20% PVA as a binder so that a self-standing nonwoven fabric base material was obtained.
  • the resulting insulating material 103 b had an average thickness of 0.200 mm, and a thermal conductivity of 0.017 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 69.6 wt %. The insulating material did not burn at all even when brought into contact with flame, as in Example 1.
  • the resulting insulating material had an average thickness of 1.05 mm, and a thermal conductivity of 0.0189 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 63.1 wt %.
  • FIG. 8 shows how flame was brought into contact with the insulating material produced in Comparative Example 1. As can be seen, the insulating material easily burned.
  • a sheet was produced under the same conditions used in Example 1, except that the gel sheet was dipped in 12 N hydrochloric acid, and allowed to stand at ordinary temperature (23° C.) for 72 hours to incorporate hydrochloric acid in the gel sheet.
  • the resulting insulating material 103 b had an average thickness of 0.656 mm, and a thermal conductivity of 0.02626 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 49.2 wt %.
  • a sheet was produced under the same conditions used in Example 1, except that the gel sheet was dipped in 12 N hydrochloric acid, and allowed to stand at ordinary temperature (23° C.) for 24 hours to incorporate hydrochloric acid in the gel sheet.
  • the resulting insulating material 103 b had an average thickness of 0.501 mm, and a thermal conductivity of 0.02585 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 47.8 wt %.
  • the insulating material did not burn at all even when brought into contact with flame, as in Example 1, but did not satisfy the required thermal conductivity of 0.024 W/m ⁇ K or less.
  • Observation of the cross sectional structure of the insulating material of Comparative Example 3 revealed that many fibers fused together, and formed double strands.
  • the double-stranded fiber had a diameter of more than 30 ⁇ m.
  • a sheet was produced under the same conditions used in Example 1, except that the gel sheet was dipped in 12 N hydrochloric acid, and allowed to stand at ordinary temperature (23° C.) for 60 minutes to incorporate hydrochloric acid in the gel sheet.
  • the resulting insulating material 103 b had an average thickness of 0.538 mm, and a thermal conductivity of 0.02663 W/m ⁇ K.
  • the silica xerogel 104 had a filling rate of 46.4 wt %.
  • the insulating material did not burn at all even when brought into contact with flame, as in Example 1, but did not satisfy the required thermal conductivity of 0.024 W/m ⁇ K or less. Observation of the cross sectional structure of the insulating material revealed that many adjoining two fibers fused together, and formed thick fiber portions.
  • An insulating material was produced without mixing the silica xerogel 104 into the nonwoven fabric fiber 119 of oxidized acrylic having a thickness of 0.241 mm and a basis weight of 53 g/m 2 .
  • the insulating material had a measured thermal conductivity of 0.042 W/m ⁇ K.
  • a nonwoven fabric fiber 119 containing 20% polyester and 80% carbon fiber, and having an average thickness of 0.130 mm and a basis weight of 10 g/m 2 was used, and an insulating material was produced without mixing the silica xerogel 104 into the nonwoven fabric fiber 119 .
  • the insulating material had a measured thermal conductivity of 0.034 W/m ⁇ K.
  • FIG. 9 shows scanning electron micrographs of the insulating materials (a composite of the nonwoven fabric fiber 119 of oxidized acrylic, and the silica xerogel 104 ) produced in Example 1 and Comparative Example 2.
  • the fiber of Example 1 is a fiber treated with 6 N hydrochloric acid.
  • the fiber of Comparative Example 2 is a fiber treated with 12 N hydrochloric acid.
  • the insulating material of Comparative Example 2 did not burn at all even when brought into contact with flame, as in Example 1. However, the insulating material of Comparative Example 2 did not satisfy the required thermal conductivity of 0.024 W/m ⁇ K or less.
  • FIG. 10 represents the relationship between the filling rate (weight %) of silica xerogel 104 , and the thermal conductivity of the insulating material. It can be seen that there is a correlation between the filling rate of silica xerogel 104 and thermal conductivity, and that preferably at least 30 weight % of silica xerogel 104 is needed to satisfy the required thermal conductivity of 0.024 W/m ⁇ K or less ( FIG. 10 ).
  • a filling rate of silica xerogel 104 higher than 80% is disadvantageous because it causes partial formation of a silica xerogel layer 101 without effective reinforcement by the nonwoven fabric fiber 119 , and makes the silica xerogel 104 easily breakable or detachable.
  • Table 2 summarizes how the filling rate of silica xerogel 104 is related to thermal conductivity, and to the amount of detached gel. As can be seen, the filling rates of 30 weight % and 80 weight % are critically meaningful for the silica xerogel 104 .
  • the preferred range of the filling rate of silica xerogel 104 for appropriately satisfying these two properties is 30 weight % to 80 weight %.
  • FIG. 11 represents the relationship between the maximum fiber diameter of the nonwoven fabric fiber 119 constituting the insulating material, and the thermal conductivity of the insulating material. As can be seen, there is a correlation between maximum fiber diameter and thermal conductivity, and the thermal conductivity decreases as a result of formation of an increased heat transfer path when the fiber diameter is larger than 30 ⁇ m, even when the same oxidized acrylic base material used in Examples 1 and 2 was used ( FIG. 11 ). The fiber diameter is therefore preferably 30 ⁇ m or less.
  • the nonwoven fabric fiber 119 have a fiber diameter of 30 ⁇ m or less, and that the silica xerogel 104 have a filling rate of 30 weight % to 80 weight %.
  • the insulating material 107 of another embodiment is shown in the cross sectional view of FIG. 12A .
  • the insulating material 107 has a three-layer structure configured from a nonwoven fabric fiber layer 106 that contains the nonwoven fabric fiber 119 but does not contain the silica xerogel 104 , and upper and lower inorganic binder layers 105 containing the silica xerogel 104 bound together with an inorganic binder. Anything that is not described is as described in First Embodiment.
  • the silica xerogel 104 and the nonwoven fabric fiber 119 are not in direct contact with each other; however, both are present in the same insulating material 107 .
  • the effects obtained in First Embodiment also can be obtained with this structure.
  • This structure can be formed more easily than the insulating material 103 b of First Embodiment.
  • the insulating material 103 b can be formed by simply applying a mixture of the inorganic binder and the silica xerogel 104 to the nonwoven fabric fiber 119 . Because the silica xerogel 104 and the nonwoven fabric fiber 119 are separated from each other, the foregoing structure allows for more freedom in the way the nonwoven fabric fiber 119 and the silica xerogel 104 are used.
  • the insulating material 107 does not differ from the insulating material 103 b with regard to properties such as thickness and components, and the concentration of the silica xerogel 104 .
  • the method of production is the same as the method for producing the insulating material 103 b of First Embodiment, except for the matter described below.
  • FIG. 12B schematically represents a method for producing the insulating material 107 .
  • a low-density powder material containing a porous powder such as the silica xerogel 104 is mixed with an inorganic binder, and the mixture is applied to a flame-retardant nonwoven fabric fiber 119 .
  • the assembly is then dried to obtain the insulating material 107 .
  • the inorganic binder is a binder for binding the low-density powder material and the nonwoven fabric fiber 119 to each other, and is typically configured from a main component, a curing agent, and a filler.
  • the inorganic binder may be a known inorganic binder.
  • the mixture is applied to both surfaces of the nonwoven fabric fiber 119 in a predetermined thickness, and dried. This completes the insulating material 107 .
  • the silica xerogel 104 is preferably one having a thermal conductivity of 0.010 to 0.015 W/m ⁇ K, and an average particle size of 5 to 50
  • the mixture may be applied to both surfaces of the nonwoven fabric fiber 119 at the same time, or one at a time in an orderly fashion. However, the way the mixture is applied and dried is not limited.
  • the nonwoven fabric fiber 119 and the silica xerogel 104 are the same as in First Embodiment. Anything that is not described is the same as in First Embodiment.
  • the silica xerogel 104 and the nonwoven fabric fiber 119 are not necessarily required to reside in the same layer, as long as these are present in the same insulating material.
  • the insulating materials of the embodiments of the present disclosure are preferably installed in various devices as a part of a heat insulating or a cold insulating structure, or between a heat-generating part and a casing of various devices.
  • the insulating materials of the embodiments can exhibit a sufficient insulating effect in narrow spaces of electronic devices, in-car devices, and industrial devices, and can be used in a wide range of applications.
  • the applicable areas include all products that involves heat, for example, such as information devices, portable devices, displays, and electric components.

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US20220227100A1 (en) * 2019-06-25 2022-07-21 3M Innovative Properties Company Nonwoven fibrous web
JP7422346B2 (ja) * 2020-05-27 2024-01-26 パナソニックＩｐマネジメント株式会社 エアロゲル構造体およびその製造方法
US12381221B2 (en) 2020-12-30 2025-08-05 Aspen Aerogels, Inc. Fibrous carbon aerogels coated with nano-thin silicon as lithium battery anodes
WO2022144736A1 (en) * 2020-12-30 2022-07-07 Aspen Aerogels, Inc. Fibrous carbon aerogels coated with nano-thin silicon as lithium battery anodes
CN118441409A (zh) * 2024-07-08 2024-08-06 成都硕屋科技有限公司 一种气凝胶绝热复合材料的制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5948314A (en) * 1994-10-20 1999-09-07 Hoechst Aktiengesellschaft Composition containing an aerogel, method of producing said composition and the use thereof
US20090258180A1 (en) * 2008-02-15 2009-10-15 Chapman Thermal Products, Inc. Layered thermally-insulating fabric with an insulating core

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004340420A (ja) * 2003-05-13 2004-12-02 Toshiba Corp 冷蔵庫
US7118801B2 (en) * 2003-11-10 2006-10-10 Gore Enterprise Holdings, Inc. Aerogel/PTFE composite insulating material
JP5615514B2 (ja) * 2008-05-15 2014-10-29 ニチアス株式会社 断熱材、これを用いた断熱構造及び断熱材の製造方法
JP5456986B2 (ja) * 2008-05-15 2014-04-02 ニチアス株式会社 断熱体
CN101619797B (zh) * 2009-06-09 2013-06-05 深圳市金士康实业有限公司 隔热膜及其制备方法
JP2011136859A (ja) * 2009-12-28 2011-07-14 Asahi Fiber Glass Co Ltd 繊維系断熱材及びその製造方法
CN104159734B (zh) * 2011-08-15 2017-11-21 纳幕尔杜邦公司 用于保护批量运输和冷链用途的可透气产品
JP5469198B2 (ja) * 2012-05-31 2014-04-09 ニチアス株式会社 断熱体
CA2876691C (en) * 2012-06-26 2018-06-12 Cabot Corporation Flexible insulating structures and methods of making and using same
JP2014035042A (ja) * 2012-08-09 2014-02-24 Panasonic Corp 断熱材
WO2014132652A1 (ja) * 2013-02-28 2014-09-04 パナソニック株式会社 エアロゲルを用いた断熱構造体
JP6738990B2 (ja) * 2014-08-26 2020-08-12 パナソニックＩｐマネジメント株式会社 断熱シートおよびその製造方法
WO2018003545A1 (ja) * 2016-07-01 2018-01-04 パナソニックＩｐマネジメント株式会社 断熱材およびその断熱材を用いた機器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5948314A (en) * 1994-10-20 1999-09-07 Hoechst Aktiengesellschaft Composition containing an aerogel, method of producing said composition and the use thereof
US20090258180A1 (en) * 2008-02-15 2009-10-15 Chapman Thermal Products, Inc. Layered thermally-insulating fabric with an insulating core

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Kappler, Iris et. al., "Surface Modification of Carbon Fibres Using Plasma Technique," March 2014, AUTEX Research Journal, Vol. 14, No 1, pp. 34-38. (Year: 2014) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210018135A1 (en) * 2018-03-30 2021-01-21 Panasonic Intellectual Property Management Co., Ltd. Heat-insulating body, heat-insulating sheet using same, and method for manufacturing heat-insulating body
US10941299B2 (en) * 2018-11-05 2021-03-09 Toyota Jidosha Kabushiki Kaisha Heat insulation coating for internal combustion engines and process for forming the same
US12195911B2 (en) 2019-05-29 2025-01-14 Panasonic Intellectual Property Management Co., Ltd. Heat insulating sheet and method of manufacturing thereof, and electronic device and battery unit using heat insulating sheet
CN111188188A (zh) * 2020-01-14 2020-05-22 南京工业大学 疏水沉淀二氧化硅复合材料的制备方法
WO2024253783A1 (en) * 2023-06-07 2024-12-12 Owens Corning Intellectual Capital, Llc Silicon dioxide aerogel composite non-woven heat insulation sheet

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